Space is a desolate void, a vacuum where no sound
can travel.
So you might think that space is extremely quiet.
You would be right, but only because you don't have
the capability to hear anything with your natural ears.
Turn your ears into radio wave receivers and suddenly space
is a constant Symphony of strange and interesting sounds.
I'm Alex Mccolgan and you're watching Astram.
And together we will find out what the sources of
these radio waves are and what they sound like.
We don't have to go too high above Earth to
already be in space.
Only 160 kilometres up.
And sound can't be heard anymore because there aren't enough
particles for sound waves to travel.
But even here in space, there are plenty of other
waves to be found.
The ones particularly interesting to us are electromagnetic waves, which
don't require other particles to travel like sound, but rather
travel by themselves through photons.
You are witnessing a form of electromagnetic radiation right now
in the form of visible light by watching this video.
However, visible light is just a tiny section of the
total spectrum of electromagnetic radiation.
It stretches from waves with extremely high frequencies to radio
waves, which have waves sometimes kilometers long.
There are observatories that look at all these different wavelengths,
and this channel has focused normally on frequencies higher than
infrared, as they can easily be converted and visualized in
visible light.
But there are also radio observatories, some orbiting Earth right
now, and we're going to check out what they have
picked up in the way you are most used to
witnessing radio waves at audio frequencies converted to sound being
in Earth's Van Allen belt or its large band of
radiation surrounding the planet, and you'll already start to hear
some very interesting sounds.
These sounds are generated by energetic particles in Earth's plasmasphere,
which are being tugged to and fro by the rotation
of Earth's magnetic field.
You see, there is a plasmasphere around Earth containing clumps
of ions and electrons.
As Earth and its magnetosphere rotate, the magnetic fields push
through these particles, accelerating them in a wave called a
plasma wave.
Similar in a way to how disturbances in Earth's oceans
can cause waves to form, you are hearing these disturbances
in the form of radio waves as they pass by
one of NASA's Van Allen Probes.
These are called chorus waves and are often heard during
Earth's dawn, which is why they are found on this
side of the planet.
An amazing type of chorus wave closer to Earth is
the Whistler mode plasma wave, which sounds like space battles
and laser fire.
These exist in the cold and denser part of the
plasmasphere and are caused by electromagnetic radiation released by lightning
striking in the atmosphere.
None.
These waves generated by these strikes can bounce around within
the magnetic field of the Earth.
And because higher frequencies travel faster than lower frequencies, that's
why these chorus waves sound like they have a fall
in pitch like a whistle.
Going further out from the plasma sphere, an opposite effect
can be heard.
This time there is a rising tone, almost like a
conversation between songbirds.
It is thought to be caused by electrons moving towards
the night side of the Earth because of magnetic reconnection
in Earth's Magneto tail, transferring their energy to the plasma
as they collide with it, as can be seen in
this simulation.
In another region within the plasmasphere we can find something
called hiss waves.
These are thought to be chorus waves which have leaked
out from the inner plasmasphere.
It sounds much more menacing and cold than the other
sounds we've heard so far.
I find these clips very interesting, but it's sometimes hard
to comprehend waves you can't see, but sound adds a
new layer of understanding when combining it with a visualization.
Even with this though, electromagnetic radiation can be a difficult
subject to graspbrilliant.org has a course specifically on radiation to
help fill in the knowledge gaps where they explain about
the electromagnetic spectrum and how it travels in waves.
So much of our day-to-day life is governed by these
waves, from seeing with our eyes, to the Wi-Fi we
receive on our phones, to the radio stations we tune
into.
Give Brilliant a go for free today and gain a
better understanding of the world around you.
By using the link brilliant.org/astram you can have a sample
of their courses.
Plus, if you opt for the annual premium subscription, the
1st 200 people will get 20% off.
And so there we have the sounds of radio waves
in space around Earth.
If you like what you saw and heard today, why
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You can donate to have your name added to this
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All the best and I'll see you next time.